This invention relates to limited slip differential mechanisms and, more particularly, relates to limited slip differential mechanisms for use in high performance automotive axle systems to eliminate wheel slippage during hard cornering maneuvers.
Automotive differentials having limited slip capabilities generally comprise clutch mechanisms which are operable to connect the differential casing to an output shaft to resist differential action in response to a loss of resistive torque bias at an output shaft. Such a differential mechanism is disclosed in U.S. Pat. No. 3,400,611 to Engle. Common open differentials provide driving torque to the wheels and permit those wheels to turn at a differential rate on cornering when the wheels have traction. If one of the wheels looses traction, however, all of the drive torque is transferred to the slipping wheel. According to the Engle patent, transmission of torque from the pinion gears to the side gears creates separating forces urging the side gears axially outwardly in a direction away from the pinion shaft. These forces are transferred to cone-shaped clutch members to increase frictional engagement of the clutch members with drum surfaces of the differential casing to provide a direct path for transmission of rotational effort to the output shaft to which the clutch member is associated.
While conventional limited slip differentials perform adequately under normal driving conditions, and particularly, in those situations where one of the driving wheels encounters ice or mud, these differentials are not ideally suited for racing maneuvers involving hard cornering. During hard acceleration through a tight turn, the weight transfer to the outside wheel is great enough to greatly reduce the tractive effort of the inside wheel. In this situation, a portion of the input torque will be transferred to the differential clutch, and if the clutch loading is insufficient, the inside wheel will spin.